<template>
  <div class="s-canvas">
    <div class="input-container">
      <input
          v-model="userInput"
          type="text"
          placeholder="请输入验证码"
          @input="validateCode"
          maxlength="4"
      />
      <canvas
          ref="canvas"
          :width="contentWidth"
          :height="contentHeight"
          @click="refreshCode"
      ></canvas>
    </div>
  </div>
</template>

<script setup>
import { ref, watch, onMounted, defineEmits } from 'vue';
import { ElNotification } from 'element-plus';

const props = defineProps({
  fontSizeMin: {
    type: Number,
    default: 25
  },
  fontSizeMax: {
    type: Number,
    default: 30
  },
  backgroundColorMin: {
    type: Number,
    default: 255
  },
  backgroundColorMax: {
    type: Number,
    default: 255
  },
  colorMin: {
    type: Number,
    default: 0
  },
  colorMax: {
    type: Number,
    default: 160
  },
  lineColorMin: {
    type: Number,
    default: 100
  },
  lineColorMax: {
    type: Number,
    default: 255
  },
  dotColorMin: {
    type: Number,
    default: 0
  },
  dotColorMax: {
    type: Number,
    default: 255
  },
  contentWidth: {
    type: Number,
    default: 112
  },
  contentHeight: {
    type: Number,
    default: 31
  }
});

const emit = defineEmits(['verify']);

const userInput = ref('');
const canvas = ref(null);
const identifyCode = ref('');

const randomNum = (min, max) => Math.floor(Math.random() * (max - min) + min);

const randomColor = (min, max) => {
  const r = randomNum(min, max);
  const g = randomNum(min, max);
  const b = randomNum(min, max);
  return `rgb(${r}, ${g}, ${b})`;
};

const generateCode = () => {
  identifyCode.value = Array.from({ length: 4 }, () => randomNum(0, 10)).join('');
};

const drawPic = () => {
  const ctx = canvas.value.getContext('2d');
  ctx.textBaseline = 'bottom';

  // Draw background
  ctx.fillStyle = randomColor(props.backgroundColorMin, props.backgroundColorMax);
  ctx.fillRect(0, 0, props.contentWidth, props.contentHeight);

  // Draw text
  for (let i = 0; i < identifyCode.value.length; i++) {
    drawText(ctx, identifyCode.value[i], i);
  }

  drawLine(ctx);
  drawDot(ctx);
};

const drawText = (ctx, txt, i) => {
  ctx.fillStyle = randomColor(props.colorMin, props.colorMax);
  ctx.font = `${randomNum(props.fontSizeMin, props.fontSizeMax)}px SimHei`;
  const x = (i + 1) * (props.contentWidth / (identifyCode.value.length + 1));
  const y = randomNum(props.fontSizeMax, props.contentHeight - 5);
  const deg = randomNum(-45, 45);

  ctx.translate(x, y);
  ctx.rotate(deg * Math.PI / 180);
  ctx.fillText(txt, 0, 0);
  ctx.rotate(-deg * Math.PI / 180);
  ctx.translate(-x, -y);
};

const drawLine = (ctx) => {
  for (let i = 0; i < 5; i++) {
    ctx.strokeStyle = randomColor(props.lineColorMin, props.lineColorMax);
    ctx.beginPath();
    ctx.moveTo(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight));
    ctx.lineTo(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight));
    ctx.stroke();
  }
};

const drawDot = (ctx) => {
  for (let i = 0; i < 80; i++) {
    ctx.fillStyle = randomColor(0, 255);
    ctx.beginPath();
    ctx.arc(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight), 1, 0, 2 * Math.PI);
    ctx.fill();
  }
};

const refreshCode = () => {
  generateCode();
  drawPic();
};

const validateCode = () => {
  if (userInput.value.length === 4) { // Ensure 4 characters are entered
    if (userInput.value === identifyCode.value) {
      emit('verify', { valid: true, code: userInput.value });
      ElNotification({
        title: '成功',
        message: '验证码正确',
        type: 'success',
      });
    } else {
      emit('verify', { valid: false, code: userInput.value });
      ElNotification({
        title: '错误',
        message: '验证码错误',
        type: 'error',
      });
    }
  }
};

// Watch
watch(() => identifyCode.value, drawPic);

// Mounted
onMounted(() => {
  generateCode();
  drawPic();
});
</script>

<style scoped>
.s-canvas {
  display: flex;
  align-items: center;
}

.input-container {
  display: flex;
  align-items: center;
}

input {
  margin-right: 10px;
  width: 50%;
  padding: 5px;
  font-size: 16px;
}

canvas {
  border: 1px solid #000;
  cursor: pointer;
}

p {
  font-size: 16px;
  color: red;
  margin-top: 10px;
}
</style>
